A. Technical Field
The present invention relates to a production process for a (poly)alkylene glycol monoalkyl ether.
B. Background Art
As to processes for producing a (poly)alkylene glycol monoalkyl ether by reacting an olefin and a (poly)alkylene glycol, for example, the following processes are disclosed: a process in which strong acid cation-exchange resins are used as the catalyst (e.g. Japanese Allowable Patent Publication (Kokoku) No. 57-35687 and Japanese Patent Application Publication (Kokai) No. 2-295941); a process in which heteropolyacids are used as the catalyst (Japanese Patent Application Publication (Kokai) No. 3-148233); and a process in which benzenesulfonic acid or toluenesulfonic acid is used as the catalyst (Japanese Allowable Patent Publication (Kokoku) No. 61-51570).
However, where the strong acid cation-exchange resins, the heteropolyacids, the benzenesulfonic acid, or the toluenesulfonic acid is used as the catalyst, there are problems in that because the (poly)alkylene glycol which is a raw material is a diatomic alcohol, the reaction tends to involve a dehydration polycondensation reaction or dehydration cyclization reaction of the (poly)alkylene glycol itself as a side reaction to form water, and this formed water tends to react upon the olefin to form an alcohol as a by-product, so the resultant selectivity to the (poly)alkylene glycol monoalkyl ether is extremely low. For instance, examples of some preferred embodiments as set forth in the Japanese Patent Application Publication (Kokai) No. 2-295941 disclose that when ethylene glycol and dodecene are reacted using Nafion H (fluorine-containing strong acid ion-exchange resin), made by E. I. Du Pont DE NEMOURS and Co., Ltd., as the catalyst to produce ethylene glycol monododecyl ether, dodecanol forms as a by-product in a proportion of 7 to 10 mol % of the ethylene glycol monododecyl ether.
A. Objects of the Invention
An object of the present invention is to provide a process for producing a (poly)alkylene glycol monoalkyl ether with high selectivity.
B. Disclosure of the Invention
The present inventors diligently studied to attain the above-mentioned object, and as a result, found that if a crystalline metallosilicate is used as the catalyst, or if the reaction between the olefin and the (poly)alkylene glycol is carried out in the presence of an alcohol, the resultant selectivity to the (poly)alkylene glycol monoalkyl ether is high, in other words, that if a catalyst with high catalytic activity such as the crystalline metallosilicate is used, not only can the selectivity be raised, but also does the reaction rate become fast to lead to the increase in the conversion, or if the alcohol which will be a by-product is added into the reaction system, the side reaction can be inhibited due to the principle of equilibrium reaction.
By the way, the inventors further got the below-mentioned two findings:
First, it was found that the addition reaction of the olefin upon the (poly)alkylene glycol includes not only a reaction of the formation of the (poly)alkylene glycol monoalkyl ether from the (poly)alkylene glycol, but also a reaction of formation of a (poly)alkylene glycol dialkyl ether. The activity of prior art catalysts is low, and no prior art disclosed the formation of the (poly)alkylene glycol dialkyl ether. However, it became clear that where a high active catalyst such as the crystalline metallosilicate is used, the (poly)alkylene glycol dialkyl ether also forms, so the resultant selectivity of the (poly)alkylene glycol monoalkyl ether is low. Therefore, it was found that when the olefin and the (poly)alkylene glycol are reacted to produce the (poly)alkylene glycol monoalkyl ether, it is effective to add the (poly)alkylene glycol dialkyl ether to inhibit the formation thereof as well.
Secondly, the crystalline metallosilicate has a problem in that where it is used for a reaction, its catalytic activity decreases with time. Thus, to solve this problem, the present inventors found that if at least a portion of the used catalyst is regenerated and then recycled as the catalyst for the reaction, the stationary activity of the catalyst can be obtained. As a result, the inventors completed the present invention.
That is to say, a process for producing a (poly)alkylene glycol monoalkyl ether, according to a first embodiment of the present invention, comprises the step of reacting a (poly)alkylene glycol and an olefin in the presence of a catalyst, thus obtaining the (poly)alkylene glycol monoalkyl ether, with the process being characterized in that a crystalline metallosilicate is used as the catalyst, and further characterized by further comprising the steps of: regenerating at least a portion of the used catalyst; and recycling the regenerated portion of the used catalyst as the catalyst for the reaction between the (poly)alkylene glycol and the olefin (herein, this production process is referred to as xe2x80x9cfirst production processxe2x80x9d).
In the first production process of the present invention, it is preferable that the regeneration of the catalyst is carried out by thermal treatment of the catalyst at 450xc2x0 C. or higher under an oxygen-containing gas atmosphere. In addition, it is preferable that the crystalline metallosilicate is a BEA type metallosilicate. In addition, it is preferable that at least a portion of a slurry containing the catalyst and an unreacted residue of the (poly)alkylene glycol is extracted, and that the catalyst is then recovered from the slurry to regenerate the catalyst. In addition, it is preferable that when the catalyst is recovered from the slurry, the (poly)alkylene glycol is also recovered from the slurry by distillation under temperature conditions of 180xc2x0 C. or lower, or that when the catalyst is recovered from the slurry, the (poly)alkylene glycol is also recovered from the slurry by distillation within 30 minutes. In addition, it is preferable that a long chain olefin is used as the olefin, when a (poly)alkylene glycol mono-higher-alkyl ether is obtained as the (poly)alkylene glycol monoalkyl ether. In addition, it is preferable that the regeneration of at least a portion of the used catalyst is carried out after the catalyst is used for 0.02 to 100 hours for the reaction.
A process for producing a (poly)alkylene glycol monoalkyl ether, according to a second embodiment of the present invention, comprises the step of reacting an olefin and a (poly)alkylene glycol in the presence of a catalyst, thus obtaining the (poly)alkylene glycol monoalkyl ether, with the process being characterized in that the reaction between the olefin and the (poly)alkylene glycol is carried out in the presence of either or both of a (poly)alkylene glycol dialkyl ether and an alcohol (herein, this production process is referred to as xe2x80x9csecond production processxe2x80x9d).
In addition, the second production process of the present invention may be further characterized by further comprising the steps of:
recovering either or both of the (poly)alkylene glycol dialkyl ether and the alcohol, both of which form as by-products in the reaction between the olefin and the (poly)alkylene glycol; and
recycling the recovered either or both of the (poly)alkylene glycol dialkyl ether and the alcohol to a system of the reaction between the olefin and the (poly)alkylene glycol.
In addition, the second production process of the present invention may be further characterized by further comprising the steps of:
recovering the resultant olefin phase and the resultant (poly)alkylene glycol phase after the reaction; and
separating the (poly)alkylene glycol monoalkyl ether from the olefin phase.
In addition, the second production process of the present invention may be further characterized by further comprising the step of recovering either or both of the (poly)alkylene glycol dialkyl ether and the alcohol, both of which form as by-products, from the olefin phase after the reaction.
In addition, the second production process of the present invention may be further characterized by further comprising the steps of:
recovering an unreacted residue of the olefin after the reaction; and
recycling the unreacted residue of the olefin to the reaction with the (poly)alkylene glycol.
In addition, the second production process of the present invention may be further characterized by further comprising the step of recycling a (poly)alkylene glycol phase, resultant from the reaction and including the catalyst, to the reaction with the olefin.
In addition, the second production process of the present invention may be further characterized in that a crystalline metallosilicate is used as the catalyst.
In addition, the second production process of the present invention may be further characterized in that: the (poly)alkylene glycol monoalkyl ether is a (poly)alkylene glycol mono-higher-alkyl ether; the olefin is a long chain olefin; the (poly)alkylene glycol dialkyl ether is a (poly)alkylene glycol di-higher-alkyl ether; and the alcohol is a higher alcohol.
These and other objects and the advantages of the present invention will be more fully apparent from the following detailed disclosure.